On 29/05/17 21:28, Andres Freund wrote: > > On May 29, 2017 12:25:35 PM PDT, Petr Jelinek <petr.jeli...@2ndquadrant.com> > wrote: >> >> Looking at the code more, the xid is only used as parameter for >> SnapBuildBuildSnapshot() which never does anything with that parameter, >> I wonder if it's really needed then. > > Not at a computer, but by memory that'll trigger the snapshot export routine > to include it. Import in turn requires the xid to check if the source is > still alive. But there's better ways, e.g. using the virtual xactid. >
It does, and while that's unfortunate the logical replication does not actually export the snapshots. It uses the USE_SNAPSHOT option where the snapshot is just installed into current transaction but not exported. So not calling the GetTopTransactionId() would solve it at least for that in-core use-case. I don't see any bad side effects from doing so yet, so it might be good enough solution for PG10. -- Petr Jelinek http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
